The carbon nanotube (CNT for short) is a novel carbon structure discovered for the first time in 1991, and is a tube obtained by rolling the graphene sheet formed by carbon atoms. The carbon nanotube has a small diameter, has a large length to diameter ratio, and is considered as a quasi-one-dimensional material. Due to excellent electrical properties, and superstrong mechanical properties, the carbon nanotube has attracted great attentions in the material field.
Due to excellent electrical properties, the single walled carbon nanotubes (SWCNTs) have wide application prospects in the electronic field, and are important candidate materials for the next generation of integrated circuit semiconductor materials. In general, the synthesized single walled carbon nanotubes (SWCNTs) are mixtures of metallic single walled carbon nanotubes (m-SWCNTs) and semiconducting single walled carbon nanotubes (s-SWCNTs), thereby seriously hindering use of the semiconducting single walled carbon nanotubes. Therefore, it is especially important to efficiently separate the semiconducting single walled carbon tubes from the single walled carbon nanotubes.
At present, the separation method mainly includes a column chromatography separation method, an ultra-high speed density gradient centrifugation method, an aqueous biphase extraction method, and a selective dispersion method. Because of simple operation, ultra-high semiconductor purity, and low losses of single walled carbon tubes, the selective dispersion has developed rapidly, but the low yield is one of the bottlenecks of this method.
At present, there is still a method of selectively dispersing and separating single walled carbon nanotubes using single polythiophene or single polycarbazole. However, the semiconducting single walled carbon nanotubes obtained by the single thiophene method have high yield, but low purity, while the semiconducting single walled carbon nanotubes obtained by the single polycarbazole method have high purity, but low yield.
Thus, how to further improve the existing carbon nanotube separation method according to its disadvantages, to achieve high-yielding separation of high-purity semiconducting single walled carbon nanotubes, becomes a novel research direction for researchers in the industrial circle at present.